Archive through July 24, 2013

[ppimentel]

Oops...Sorry, but the problem is my engine stops 'like the key was turned off' when it gets HOT.

Just got it back from the machine shop, new piston, rings, values done.... and it runs really good, but when it gets hot it stops.

I saw in the 'Frequently asked' that it's due to a sticking exhaust value ??? Is this true ?

I thought it was due to the coil because it also get really hot and I just bought the blue coil and points saver from Kirk.

Not sure what to do .....

 

[kmcconaughey]

Paul, if the engine was recently rebuilt I'd say it wouldn't be the exhaust valve sticking. Sounds more like something was not wired correctly when you installed the PointSaver. Did you remember to remove the condenser?

PointSaver Instructions

 

[ppimentel]

Hi Kraig,

Yes...I did. I'm thinking of putting the old coil back and trying it out. If it still does it I was going yank the points saver and put it back to the original stuff.

I don't know, but you know when I did finally get it going again it did start to sputter again until I gased it and it seemed to run until I finished the lawn anyway.

I might try the MMO before going back to the original stuff...I don't know.

 

[kmcconaughey]

Paul, is it just the coil that is getting hot? If the engine itself is running too hot, perhaps it is running a bit too lean. Try adjusting the carb to enrich it a slight bit. You did not mention which model Cub or what size engine. Here's some excerpts from the 70/100 Operator's Manual on adjusting the carb:

 

[ppimentel]

Kraig....wow, thanks for the carb adjustment.

I almost did the same but I'll follow these instructions.... I do tend to go on the lean side of things and I thought that would be better.

All I know is that the coil gets hot and I was thinking that it was breaking down because it starts right back up when it cools down.

But then again, maybe the value is sticking because when hot trying to restart it...it backfires...really loud.

It's a 123/4 (manual shift) 12hp

 

[dtanner]

Paul Pimentel

What point setting did you use to set the points??? A new engine won`t have carbon to make it back fire when restarting . That would happen if you had a rich mixture and carbon on the piston. could you tell us what the point gap is now ??? There is no need for a condenser with the point saver.

 

[ppimentel]

Hi Donald,

I think the gap is .20, the point saver had the gap listed because I bought new points to.

I'm just thinking of removing the new stuff and going with the original setup because it's getting unreliable. It's stops running like whne your 3/4's of the way done and you have to wait a half hour for it to cool down enough.

Maybe I should check the points again....and the next time that engine is out (hopefully not though) I'm going to cut that frame to allow easier access to the bottom screw of the points cover....what a pain that is.

 

[dfrisk]

PAUL - Kohler engines should be set rich, not to the point of black smoke from the exh, but typically about 1/4 to 3/8's turn of the High Speed fuel screw COUNTER-CLOCKWISE from the point of best operation at no load. I'd turn that screw 1/4 turn and try running it again before you make any other changes. And if it cures the stalling I'd consider giving it another 1/8 to 1/4 turn. The blue Bosch coil is a good coil. They will get warm when running for a while, like an hour or so, almost too hot to touch.

Lean fuel/air mixture burns really quick and H-O-T, a rich mixture burns slower and cooler. You don't want Hot on an air-cooled engine. They run plenty enough HOT the way it is.

 

[ppimentel]

okay...Dennis,

I'm going to recheck the points gap & redo the carb adjustment and follow your guidelines about running it a little richer than leaner.

Really a big Thank-You for everyone's input .... maybe someday I'll be able to do the same.

 

[dtanner]

Paul Pimentel

I think most of us has drilled a hole in the frame so a screwdriver can be used to remove the bottom screw on the points cover. I use all allen head screws so the screw does not fall off when installing or removing the screw. A small dab of grease will hold the screw in place.

The point saver instructions mention .020 as a point setting. But That setting can be way off ! I set my points in my 125 and ended up with .025 to get the engine timed. You engine might start at .020 but it will not be correct and not work as it should. Poping thought the carb is a sign of to early a point setting. I think timing is more your issue and would go over the fac and reset the timing. 0.020 is not a set in stone setting for timing on our Cub engines.

 

[sblunier]

And to add to Denny's words of wisdom, the extra 1/4 turn rich makes sure that when the governor calls for power, it's there, no stumble, no hesitation, just there!!! (evident on a fast throttle up from sustained idle......it should pick it right up with no hesitation)

Adjustment: Turn IN to the point of stumbling, OUT to the point of stumbling/loading up, split the difference , and then back OUT an additional 1/4 turn to rich.......

 

[tbdavis]

Alex - what size rear tires on your 71? Like em!

 

[dtanner]

Terry Davis

They look like 23 8.5 12 tru powers ; I put the same tires on my 125.

 

[tbdavis]

Might be 8.5s - just put a pair on my 73 but just from the pic I just can't tell for sure. Whatever's on his are going on my 71.

 

[asmith]

Terry D.- They're 6-12 Carlisle tru powers. I have a set of IH wheel spacers and have been toying with the idea of putting on a second set. I need to locate a set of IH lug bolts for the inside. You know more $$. My brother had a set but either gave them away or traded them to a fellow cub nut.

 

[mkopishke]

I have a 122 that clutch wants to stay engaged. You can tap the disks to break the loose again but it just seems to want to go back to being stuck. It seems to be the front one (near the engine) more then the back one.

The gap looks good, it's almost like the disks are sticking to the friction disk.

Easy fix or does the clutch need to overhauled?

 

[gpapa]

Finally got some cub stuff done

! Installed the rear hitch, Xtreme suitcase weight bar, super steering upgrade. Electric lift went on the fritz as soon as upgrades were done - of course! Installed the spare and was off cutting again. The extra weight really helps with the steeper slopes and the slippery stuff.

 

[kide]

Just to back up what Dennis and Steve said about running on the richer side of "good" ... I'm currently going through the steps on a 1700 CC motorcycle engine to retune the fuel injection and just moving the Air/Fuel mixture down from the theoretically "perfect" 14.6:1 A/F ratio to 14.2:1 dropped the cylinder head temperature from 260 degrees to 225. On an air cooled engine, that's a big difference.. Of course it's handy on the Cub to have a carb with a high speed mixture screw - the smartest thing I did when I put the crate engine in mine in '95 was to keep the carb off the original engine and put the new carb on the old engine before I sold it...

 

[tbdavis]

Alex - thanks for getting back on the tires. Duals would be nice but hard to improve on perfection! I'm curious if 8.5s were an option when new. Anyway - thanks much!

 

[kmcconaughey]

Terry, yes, 23 x 8.5-12 tires were an option on the 71.